Importing from other formats
OmniPlan understands several other applications' file formats. You can open files of these types in OmniPlan the same way you would open an OmniPlan document. The file is imported into a brand new OmniPlan document, which you can then edit, save, or export.
Microsoft Project (.xml, .mpx, .mpp, and .mpt) Documents created in Microsoft Project XML, MPX, or MPP formats can be opened by OmniPlan, with a few limitations. Note that while OmniPlan can read MPP files, it can't write them. For the best compatibility going back and forth between OmniPlan and Microsoft Project, use the XML format. See the Microsoft Project support section for a list of the compatibility limitations.
Comma-Separated Values (.csv) and Tab-delimited text files (.txt) OmniPlan can read comma-separated or tab-delimited values from a plain-text file. To see how the data in a CSV file should be formatted, export an OmniPlan document as a CSV file and open the result in any text editor. Tab-delimited files are formatted like CSV files, except that tab characters are used instead of commas to separate fields.
OmniOutliner 3 (.oo3 and .ooutline) Task lists can be imported from OmniOutliner files. A column mapping dialog appears, where you can choose which outline column should correspond to which field of task information. If the outline has multiple levels of hierarchy, task groups are created.
OmniGraffle (.graffle) Task lists can be imported from OmniGraffle diagrams. The title of an object becomes the task title, and the hierarchy of connection lines determines the hierarchy of task groups.